[1] Univ Cologne, Dept Med, Ctr Hlth Serv Res Cologne, D-50933 Cologne, Germany
[2] Univ Educ Freiburg, Inst Psychol, Freiburg, Germany
[3] Univ Hosp Cologne, Dept Visceral & Vasc Surg, Cologne, Germany
[4] Univ Glasgow, Div Commun Based Serv, Sect Gen Pratice & Primary Care, Glasgow G12 8QQ, Lanark, Scotland
[5] Univ Hosp Cologne, Dept Gynecol & Obstet, Cologne, Germany
[6] Univ Hosp Cologne, Ctr Integrated Oncol, Cologne, Germany
[7] Univ Hosp Cologne, Dept Internal Med Mol Tumor Biol & Tumor Immunol, Cologne, Germany
[8] Univ Cologne, Inst & Policlin Occupat & Social Med, Cologne, Germany
[9] Univ Cologne, Div Med Sociol, Cologne, Germany